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Preparation of gold, silver and platinum colloid solutions by precursors decomposition in low temperature plasma
Brožek, Vlastimil; Kutílek, Zdeněk; Mastný, L.; Sýkora, V.; Benešová, L.; Sofer, Z.
2013 - English
Liquid precursor decomposition in the low temperature plasma generated by WSP® was used for synthesis of precious metals nanoparticles. The gold in the form of H[AuCl4], silver in the form of AgNO3 and platinum in the form of H2[PtCl6] were used to generate colloid solutions with concentration of 5 mg.l-1 – 70 mg.l-1 and particle size of 20 nm – 120 nm. The solution contained elevated concentration of nitrite and nitrate ions due to the reaction of plasma with nitrogen form air. In order to reduce the concentration of nitrite and nitrate ions the plasma generated nanoparticles was projected by plasma torch to the ammonium chloride solution. Other way used for reduction of NO3- and NO2- concentration was optimization of geometry of plasma system. The other way was also by application of shrouding effect by nitrogen and ammonia gas. The size of nanoparticles and their concentration can be influenced by geometry of plasma torch, composition of carrier gas and by geometry of
Keywords:
colloidal suspension; gold nanoparticles; silver nanoparticles; platinum nanoparticles; plasma generator; low temperature plasma
Available at various institutes of the ASCR
Preparation of gold, silver and platinum colloid solutions by precursors decomposition in low temperature plasma
Liquid precursor decomposition in the low temperature plasma generated by WSP® was used for synthesis of precious metals nanoparticles. The gold in the form of H[AuCl4], silver in the form of AgNO3 ...
Thermal plasma gasification of organic waste and biomass
Hrabovský, Milan
2013 - English
The paper presents description of thermal plasma gasification processes. Analysis of energy balances of plasma gasification is presented, kinetics of the gasification process is discussed and relations between particle size, reaction temperature and gasification rate are analyzed. Examples of results of gasification of biomass and pyrolysis oil from used tires are given. Syngas with high heating value, high hydrogen content and low tar contamination is produced by plasma gasification.
Keywords:
Thermal plasma; plasma gasification; syngas
Available at various institutes of the ASCR
Thermal plasma gasification of organic waste and biomass
The paper presents description of thermal plasma gasification processes. Analysis of energy balances of plasma gasification is presented, kinetics of the gasification process is discussed and ...
Heat and Particle Deposition on the Plasma-Facing Components
Podolník, Aleš; Pánek, Radomír; Komm, Michael; Dejarnac, Renaud; Gunn, J. P.
2013 - English
The interaction of plasma with plasma-facing components (PFCs) in tokamaks is of increasing interest because of implications for ITER and next-step devices. The heat and particle fluxes interacting with solid objects can be studied by means of particle-in-cell (PIC) simulations. The aim of this work is to use the existing family of PIC codes SPICE to simulate the heat and particle flux distribution on PFCs. The output of the simulations is then used in new heat equation solver, which calculates the temperature of the PFCs. This solver provides us a testbed for the parallel sparse matrix code development as well as for the complex application aimed at study of the melting of tiles.
Keywords:
plasma; tokamak; ITER
Fulltext is available at external website.
Heat and Particle Deposition on the Plasma-Facing Components
The interaction of plasma with plasma-facing components (PFCs) in tokamaks is of increasing interest because of implications for ITER and next-step devices. The heat and particle fluxes interacting ...
Comparison of holographic setups used in heat and mass transfer measurement
Doleček, Roman; Psota, Pavel; Lédl, Vít; Vít, Tomáš; Kopecký, V.
2013 - English
The authors of the paper deal with measurement of heat and mass transfer for several years and they have frequently used few techniqes for measurement of refractive index distribution based on holographic interferometry. Some of the well known techniques have been modified some and some new ones developped. Every technique could be applied with success in different type of meassurement and obviously every one has set of properties making them unique. We decided to digest few different basic techniques and describe its properties in this paper with the aim to help the reader select the proper one for their measurement. The list of techniques and its properties is not comprehensive but schould serve as a basic orientation in the field.
Keywords:
Digital holography; Holographic setup; Heat and mass transfer measurement
Available at various institutes of the ASCR
Comparison of holographic setups used in heat and mass transfer measurement
The authors of the paper deal with measurement of heat and mass transfer for several years and they have frequently used few techniqes for measurement of refractive index distribution based on ...
Measurement of Vibration Mode Structure for Adaptive Vibration Suppression System by Digital Holography
Psota, Pavel; Lédl, Vít; Doleček, Roman; Mokrý, P.; Kopecký, V.
2013 - English
Previously the frequency-shifted digital holographic interferometry (FSDHI) for measurement of vibration amplitudes in range of nanometers was introduced and verified by authors [1,2]. The method FSDHI addressed some of the drawbacks of the conventional methods and was used mainly for piezoelectric transformer vibration amplitudes and mode structures measurement [3]. The limiting factor for application of this method is the maximal measured value of the vibration amplitude without the risk of ambiguity. The value is approximately 80nm for the frequency doubled Nd: YAG line. Since FSDHI enables us to precisely measure vibration amplitudes over the whole inspected area with very high lateral resolution, it could also be a very useful tool for measurement of vibration amplitudes and mode structures for research in the field of adaptive suppression systems. Such a measurement would provide a necessary feedback about the system behavior.This was the reason why we put an effort
Keywords:
digital holography; vibration measurement; vibration suppression
Available at various institutes of the ASCR
Measurement of Vibration Mode Structure for Adaptive Vibration Suppression System by Digital Holography
Previously the frequency-shifted digital holographic interferometry (FSDHI) for measurement of vibration amplitudes in range of nanometers was introduced and verified by authors [1,2]. The method ...
Preparation of multiphase materials with spark plasma sintering
Mušálek, Radek; Dlabáček, Zdeněk; Vilémová, Monika; Pala, Zdeněk; Matějíček, Jiří; Chráska, Tomáš
2013 - English
Spark plasma sintering (SPS), also called Field Assisted Sintering Technique (FAST), represents a novel method of preparation of sintered materials from powders. The main advantage of the SPS method is a high achievable heat rate (>200 °C/min) and high sintering temperatures (up to 2200 °C in our laboratory). Combination of high heating rate, rather high pressures (up to 80 MPa) and electric field fluctuations leads to an effective sintering and significant reduction of sintering time for both coarse-grained and nanocrystalline powders. Composite materials may be easily obtained by mixing or layering of different powders. The paper will introduce several examples of multiphase materials sintered by SPS at our institute and the establishment of procedures for routine testing of sub-sized specimens.
Keywords:
spark plasma sintering; powder metallurgy; composites; multiphase materials; FeAl matrix
Available at various institutes of the ASCR
Preparation of multiphase materials with spark plasma sintering
Spark plasma sintering (SPS), also called Field Assisted Sintering Technique (FAST), represents a novel method of preparation of sintered materials from powders. The main advantage of the SPS method ...
First measurements with U-probe on the COMPASS tokamak
Kovařík, Karel; Ďuran, Ivan; Stöckel, Jan; Seidl, Jakub; Šesták, David; Brotánková, J.; Spolaore, M.; Martines, E.; Vianello, N.
2013 - English
A complex electrostatic-magnetic probe diagnostics, baptized as ‘U-probe’, has been installed on COMPASS tokamak recently. Probe composes of two identical towers. Each tower houses 3 radially spaced sets of 3D coils, triple probe and rake probe – array of six Langmuir probes. The U-probe measures electric and magnetic properties of the filamentary structures in the edge plasma, particularly the floating potential profile and local magnetic field within the plasma filaments. Contribution presents first tests and results obtained.
Keywords:
plasma; tokamak
Fulltext is available at external website.
First measurements with U-probe on the COMPASS tokamak
A complex electrostatic-magnetic probe diagnostics, baptized as ‘U-probe’, has been installed on COMPASS tokamak recently. Probe composes of two identical towers. Each tower houses 3 radially spaced ...
Dust Observation in the COMPASS Tokamak Using Fast Camera
Odstrčil, M.; Mlynář, Jan; Weinzettl, Vladimír; Háček, Pavel; Berta, M.; Szabolics, T.; Bencze, A.
2013 - English
The dust grains were observed over a thousand discharges in the tokamak COMPASS. A novel method for semi-automatic extraction and tracking of dust grains using a relatively low frame-rate camera (370 fps) was proposed. Radiation lifetime, time evolution and the acceleration of the dust grains were studied. The measured dust velocities roughly correspond to a simple model. However, slow dust particles are signicantly aected by local plasma properties and initial release conditions that cannot be determined in our experiment
Keywords:
COMPASS; tokamak
Fulltext is available at external website.
Dust Observation in the COMPASS Tokamak Using Fast Camera
The dust grains were observed over a thousand discharges in the tokamak COMPASS. A novel method for semi-automatic extraction and tracking of dust grains using a relatively low frame-rate camera ...
Possible way to prepare nanoparticles from aerosols released at plasma deposition
Brožek, Vlastimil; Mastný, L.; Moravec, Pavel; Ždímal, Vladimír
2012 - English
During plasma deposition of powdered metals or inorganic compounds using WSP® generator, they interact with the plasma having temperature between 25000 and 30000 K. As a result, they melt, evaporate, thermally decompose, get ionized and/or react chemically both with plasma-forming medium and with the surrounding atmosphere or carrier gas. An experimental apparatus was constructed enabling us to capture aerosol particles emitted from the surface of the free flying particles (FFP) heated in a stream of plasma. In this work we studied content, composition and size distribution of nanosized particles of Ag and oxides of Al, Ti, Cr and W, released during plasma deposition process. These particles were analyzed by dynamic light scattering - photon correlation spectroscopy using instrument MALVERN, and with aerosol spectrometers SMPS 3936 and APS 3321.Concentration of aerosols containing nanoparticles of silver or metal oxides with diameters below 100 nm was found to be in the range 85 to
Keywords:
plasma spraying; aerosol technology; nanoparticles production; measurement of particle size distribution
Fulltext is available at external website.
Possible way to prepare nanoparticles from aerosols released at plasma deposition
During plasma deposition of powdered metals or inorganic compounds using WSP® generator, they interact with the plasma having temperature between 25000 and 30000 K. As a result, they melt, evaporate, ...
Development of large aperture elements for active and adaptive optics
Kmetík, Viliam; Nemcová, S.; Jiran, L.; Stranakova, E.; Inneman, A.
2012 - English
Large-aperture elements for laser active and adaptive optics are investigated in collaboration within IOP AcSci CR, FEng CTU and 5M. A bimorph deformable mirror for high-power lasers based on a lightweight structure with a composite core is currently in development. In order to realize a sufficiently large working aperture we are using new technologies for production of core, bimorph actuator and DM reflector. Detailed simulation of components and structure is validated by measurement and testing. A research of DM actuation and response of a complicated mirror structure needed for an accurate control of a deformation is performed. Testing of samples and subscale measurements are currently performed, measurement of a complete structureis in preparation
Keywords:
laser active and adaptive optics
Available at various institutes of the ASCR
Development of large aperture elements for active and adaptive optics
Large-aperture elements for laser active and adaptive optics are investigated in collaboration within IOP AcSci CR, FEng CTU and 5M. A bimorph deformable mirror for high-power lasers based on a ...
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